It is known in the art to sense and sum pressures in plural hydraulic circuits and resultingly control displacement of pumps in the circuits or the discharge flow of pressurized fluid within the circuits. However, the prior art does not disclose a torque-limiting system having plural hydraulic circuits wherein the fluid in the circuits is not mixed and with the motors of the hydraulic circuits having their outputs mechanically summed in a common torque-summing output device with the maximum torque not being exceeded regardless of whether two or more hydraulic circuits, each having a motor connected to the torque-summing device, have their circuits pressurized.